Compute workloads are inherently not pre-emptible for long periods on current hardware. As a workaround for this, the pre-emption timeout for compute capable engines was disabled. This is undesirable with GuC submission as it prevents per engine reset of hung contexts. Hence the next patch will re-enable the timeout but bumped up by an order of magnitude. However, the heartbeat might not respect that. Depending upon current activity, a pre-emption to the heartbeat pulse might not even be attempted until the last heartbeat period. Which means that only one period is granted for the pre-emption to occur. With the aforesaid bump, the pre-emption timeout could be significantly larger than this heartbeat period. So adjust the heartbeat code to take the pre-emption timeout into account. When it reaches the final (high priority) period, it now ensures the delay before hitting reset is bigger than the pre-emption timeout. v2: Fix for selftests which adjust the heartbeat period manually. v3: Add FIXME comment about selftests. Add extra FIXME comment and drm_notices when setting heartbeat to a non-default value (review feedback from Tvrtko) Signed-off-by: John Harrison <John.C.Harrison@Intel.com> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20221006213813.1563435-4-John.C.Harrison@Intel.com